rose from less than 5 per year prior to 1990 to more than 300 per year from 2007 to 2011. However, the application of regime shift related concepts is still contested.

Although there is not agreement on one definition, the slight differences among definitions reside on the meaning of stability - the measure of what a regime is - and the meaning of abruptness. Both depend on the definition of the system under study, thus it is relative. At the end it is a matter of scale. Mass extinctions